This invention relates generally to a klystron amplifier through which a relativistic electron beam is propagated between input and output cavities within a grounded drift tube having a resistive wall.
The propagation of a relativistic electron beam through the drift tube of a klystron device for amplification of microwave energy by beam current modulation is generally well known in the art as exemplified by U.S. Pat. Nos. 4,480,210, H6 (Statutory Invention Registration), 4,949,011 and 5,386,177 to Priest et al., Friedman et al., Mann and Uhm, respectively. According to such prior art, beam current modulation is deemed to be a linear function of drift tube distance between cavities. Thus, in an effort to reduce the overall length of the klystron amplifier in order to achieve a desired gain, drift tube propagation of the electron beam was interrupted by gaps intermediate the input and output cavities according to the teachings in the aforementioned patents to Priest et al., Friedman et al. and Mann. According to applicant's aforementioned prior patent to Uhm, interaction of the electron beam during propagation through a drift tube internally modified to enclose a body of dense plasma, is relied on to shorten drift tube distance between cavities.
It is therefore an important object of the present invention to provide a klystron amplifier through which drift tube propagation of a relativistic electron beam is conducted without interruption or internal drift tube modification to shortened distance between resonator cavities in order to obtain maximized beam current modulation.